Treatment of hydrocarbon distillates



July 28, 1942.

w. L. BENEDVlc'r TREATMENT OF HXDROGARB-ON DISTILLATES Fil'ed March 3l,1939 Patented July 28, 1942 TREATMENT F HYDROCARBON DHSTILLATES Wayne L.Benedict, Chicago, Ill., assigner to Universal Oil Products Company,Chicago, lll., a

corporation of Delaware Application March 31, 1939, Serial No. 265,218

3 Claims. (Cl. 196-30) The present invention is particularly directed tothe treatment of hydrocarbon distillates of gasoline boiling range andmore specifically to the treatment of cracked motor fuels obtained bythe thermal decomposition of petroleum oils, or of oils or tars,obtained by the destructive distillation of oil shales, coal tars, Woodtars, and the like.

The refining of cracked gasoline distillates has been achieved in thepast by one of several methods. Outstanding among these is the use ofsulfurlc acid by which sulfur and other undesirable components ofthe-gasoline are removed.

Other refining methods which have been used include contacting crackedmotor fuels with natural and activated adsorbent earths. This process isoften used in conjunction with gum inhibitors which increase the storagestability and decrease the copper dish gum content of the finished motorfuels. The use of inhibitors sometimes replaces other refining methodsentirely.

Untreatedmotor fuel usually requires sweetening to improve the odor andthis is done by one of several methods, such as the well known doctortreating method, copper sweetenlng, or hypochlorite sweetening. Theaddition of the inhibitor to prevent auto-oxidation and gum formationfollows the sweetening step.

Still another method which has been used commercially is the treatmentof cracked distlllates by contact at elevated temperatures with alloysof zinc and copper, zinc-containing ores, and the like in the presenceof hydrochloric acid. The acid is either injected simultaneously withthe gasoline or else the latter is pretreated with strong hydrochloricacid solution. These include synthetic zinc-silica hydrogels. 'Iheprocess produces gasoline of good color and storage stability. It iswith modications of the above process that the present invention isconcerned.

In one specic embodiment the invention comprises treating crackedgasoline with relatively strong hydrochloric acid, separating thegasoline, contacting it in a primary treating step at treatingconditions with a partially used powdered reagent from a later step,said reagent containing zinc or an oxide of zinc as one major treatingcomponent, separating the gasoline from the spent reagent andhigh-boiling bottoms, contacting said separated gasoline with freshpowdered treating reagent in a second treating step at treatingconditions, removing the treated gasoline, returning the partially spentreagent and high-boiling bottoms to the aforementioned primary treatingstep,

recovering the spent reagent 5.5

after the primary step, regenerating said spent reagent by treating witha volatile alkaline reagent such as ammonia or ammonium hydroxidefollowed by burning in the presence of air, and returning said reagentto the second treating step.

It has been noted that during the earlyY stages videda method ofregenerating the reagent so that it can be used over again for anindefinite number of times.

According to the present invention the gasoline is contacted atatmospheric temperature with a concentrated solution of hydrochloricacid (approximately 25-40%) the sludge permitted to settle out andwithdrawn to Whatever method of disposal has been provided for it.Contacting with the acid may be carried out Aby any of a number of ways,among which the countercurrent types are the most suitable. The acidtreated gasoline is heated by passage through a heat exchanger and ifnecessary through a coil disposed in a furnace. The gasoline then mixeswith heavy bottoms containing suspended I in them partiallyspent reagentfrom the second treating step and the mixture passes through a suitableprimary reactor where the treating eiect occurs. Generally thetemperatures used in this step are moderate. If the gasoline werefractionated at this point it would be found to be of good color andrelatively low gum content. The reactor may be any suitable type, thepurpose being largely to insure adequate contact and sufficient time forthe reaction to take place. Among those which have been found useful arebaie columns, orifice mixers, mechanical agitators, etc. The reaction iscarried out at sufficient pressure to'maintain the major portionA of thegasoline in the liquid phase (1GO-500 pounds per square inch) andtemperatures of the order of 250 F. to 400 F. and may be suitably of theorder of 300 F. The partially treated gasoline then passes to a flashseparator where the pressure is reduced and the gasoline is flashed oif,while the mixture of heavy bottoms and v1 into sludge separator I2.

spent reagent is continuously withdrawn 'and passed through a devicewhereby the polymers are removed from the reagent. Such a device maycomprise a lter press, or a settler from which the spent reagent can beremoved readily. The vapors from the flash separator are cooledsufficiently to condense ythem and passed to a slurry pot where freshreagent is added and the mixture agitated to keep the powder insuspension. The mixture is pumped through a heating coil into a secondreactor similar to that employed in the rst or primary treating stage.The temperature is usually somewhat higher than that used in therststage, being of the i order of 30D-550 F. and preferably about 400- 450"F. The pressure range used is approximately the same as for the primarystep. The mixture of reagent and distillate then passes into afractionator and the finished gasoline recovered. The high-boilingbottoms and suspended reagent are continuously removed from thefractionator and returned hot to the primary treating step.

The spent reagent from the primary step is separated from high-boilingpolymers and may be washed with naphtha if desired to remove theremaining occluded polymers. The reagent is treated with a. solution ofammonium hydroxide or gaseous ammonia or other Volatile alkalinecompounds such as amines, etc., to convert any remaining zinc chlorideto the hydroxide. The mixture is passed to a furnace or kiln and heatedin the presence of air to temperatures in excess of 900 F. but suitablybelow 1800 F. to prevent substantial sublimation of zinc oxide. In thisway carbonaceous material 'is burned off and zinc sulde is converted tothe oxide. After regeneration the reagent is taken from the kiln tostorage from which it may be passed to the second treating step. Theammonia used is recovered as ammonium chloride which sublimes during theburning step and may be taken into solution and converted to ammonia ina separate step by treatment with burned lime.

One embodiment of the present invention is illustrated diagrammaticallyby the attached drawing which should not be construed as limiting it tothe exact conditions or apparatus used. The apparatus has not been drawnto scale or proportioned exactly.

The gasoline enters the system through line I, valve 2, pump 3 and valve4 and is mixed in line 5 with hydrochloric' acid which enters from line8, valve 9, acid pump l0 and valve II. The hydrochloric acid andgasoline are thoroughly mixed in a mixer 6 and passed through valve Theacid sludge is wthdrawn from the separator through line I3 and valve I4.'I'he gasoline passes through line I5, valve i6, heat exchanger I1 andis mixed in line I9 with high-boiling material containing.

partially spent powdered reagent from fractionator 40, by way of linei8. A heating coil may be interposed in line I9 providing additionalheat is needed. The mixture passes through valve 20 into the primaryreactor 2l which is illustrated as being a bailied tower but may be anysuitable arrangement wherein suii'icient contact and time for reactiontakes place. Them'ixture leaves the reactor by line 22 and valve 23,passes into ash separator 24 at a reduced pressure and maintained atsumciently high temperature by means of coil 2d' so that the gasoline isashed overhead through line 25 and valve 26. The mixture of heavybottoms and spent reagent is Withdrawn through line 26" and valve 26"'to the separator and regeneration plant which will be described later.The gasoline vapors pass through line 25, valve 26 and heat exchanger 26where they are cooled suliciently to condense them. In the slurry pot 21which may suitably be an inclosed vessel equipped with a mechanicalstirrer 21 or other device for maintaining the reagent in suspension,the gasoline distillate is mixed with fresh treating reagent from hopper5l', line 5l and valve 51". The reagent is supplied to hopper 51 from.reagent storage 51 by means of conveyor line 28 and valve 28.

i The slurry passes through line 29 and valve 30 .by means of pump 3lthrough valve 32 into coil 33 which is disposed in furnace 34. Thepressure is increased by means of pump 3l to the desired point which mayDe approximately 10G-500 pounds per square inch, although ordinarilypressure of -250 pounds is adequate. The gasoline then passes throughline 35 and valve 36 into the second reactor 31 which may be similar toreactor 2| and wherein the gasoline is reacted with the fresh treatingreagent. The gasoline is drawn through line 38 into yfractionator 40.Gasoline vapors pass overhead through line 4I containing valve 42 andare taken through suitable coolers not shown to storage. Smallquantities of ammonia, ammonium hydroxide or caustic solution may beinjected into the run-down line in order to prevent corrosion. Thegasoline is sweet, of good color, low gum content, and has a goodstorage life as well as a substantially reduced sulfur content. Thepolymersy or high-boiling bottoms formed during treating together withthe partially spent reagent are drawn through line I8 and valve 43 andrecirculated as was previously described in line I9 and thence throughvalve 20 into the rst reactor.

Line 45 and valve 44 serve as a means for draining the fractionator 40.The mixture of polymers and spent reagent from the flash separator 24 iswithdrawn through line 26' and valve 26v into separator 46 which may bea lter press or any sort of separating device whereby the polymers maybe withdrawn from the system as through line 41 and valve 48. The spent'reagent is taken by means of conveyor line 49 and valve J9 to mixer 50where it is thoroughly mixed with gaseous ammonia or a solution ofammonium hydroxide or other volatile alkaline material entering throughline 5I and valve 52. The reagent is then conveyed as indicated by line53 and valve 53 to a kiln or furnace 54 Where it is heated to atemperature in excess of 900 F. with controlled quantities of air inorder to reactivate the reagent and burn therefrom the hydrocarbonaceousmaterial. Thel combustion products together with sublimed ammoniumchloride pass out of the systeml'ythrough line 55 and valve 55' and maybe passed to a suitable cooler` and recovery system Where the ammoniumchloride is collected and from which the ammonia may be recovered bysuitable means. The regenerated reagent is conveyedlas by line 56 andValve 56' to reagent storage 51 jfrom which it is taken to hopper 51' bymeans of conveyor line 28 and valve 28'. The reagent can be introducedinto the slurry pot by any convenient method. For instance the reagentcan be made into a slurry with a small portion of gasoline or heavybottoms in hopper 51' and pumped into slurry pot 3l; or the hopper maybe tted with a proportioning device for continuously adding the polymersformed and regenerated by mixing powdered reagent. therewith vammoniumhydroxide solution and The following example is given to illustrate theburning at a maximum temperature of 1400 F. process and should not beconstrued as limiting in the presence of air. After regeneration the itto the exact conditions given therein. 5 reagent was found to be equallyas active as A Mld-Continent cracked gasoline was treated fresh reagentand was used again in the process.

with 2 pounds per barrel of 35% hydrochloric I claim as my invention:

acid solution and passed through the process del. A process for refininghydrocarbon distilscribed in the foregoing speciiications. The relateswhich comprises subjecting the distillate to agent used comprisedessentially 10% zinc oxide l0 the action of zinc-containing reagent intwo aucon pumice ground to pass 100 mesh. The temcessive stages,supplying fresh zinc-containing perature maintained in the primarytreating step reagent to the second of said stages and therein was 300F. at a pressure of 150 pounds per utilizing the reagent to effect adesulfurization square inch. The temperature maintained in of thedistillate, and supplying thus used rethe second treating step was 400F. and the 15 agent from the second stage to the rst of said pressurewas 200 pounds per square inch. The stages to improve the distillatewith respect to amount of reagent added to the second treating gum andcolor during the treatment in the inistep was 5 pounds per barrel ofgasoline. 'The tial stage. treated gasoline was 30+ color, had a sulfurcon- 2. The process as dened in claim l further tent of 0.1%, copperdish gum of 5 mg. and 20 characterized in that the distillate ispre-treated oxygen bomb induction period of 600 minutes. withhydrochloric acid. v The untreated gasoline entering the plant was 3.The process as defined in claim 1 further yellow color, contained 0.18%sulfur, had 150 mg. characterized in that said reagent is regenerated ofcopper dish gum and an induction period of after its use in said rststage and then returned 100 minutes. Y 25 to said second stage.

The spent reagent was separated from the WAYNE L. BENEDICT.

